<template>
  <div class="article-container">
    <!-- 导航栏 -->
    <van-nav-bar class="page-nav-bar" left-arrow title="黑马头条" @click-left="$router.back()"></van-nav-bar>

    <div class="main-wrap">
      <!-- 加载中 -->
      <div v-if="loading" class="loading-wrap">
        <van-loading color="#3296fa" vertical>加载中</van-loading>
      </div>

      <!-- 加载完成-文章详情 -->
      <div v-else-if="article.title" class="article-detail">
        <!-- 文章标题 -->
        <h1 class="article-title">{{ article.title }}</h1>

        <!-- 用户信息 -->
        <van-cell class="user-info" center :border="false">
          <van-image 
            class="avatar" 
            slot="icon" 
            round 
            fit="cover" 
            :src="article.aut_photo" />
          <div slot="title" class="user-name">{{ article.aut_name }}</div>
          <div slot="label" class="publish-date">{{ article.pubdata | relativeTime }}</div>
          <!-- 模板中的 $event 是事件参数 -->
          <!-- 当我们传递给子组件的数据既要使用还要修改，
            传递： props  
              :is-followed="article.is_followed":is-followed="article.is_followed"
            修改：自定义事件
              @update-is_followed="article.is_followed = $event"
            简写方式：在组件使用v-model 自动生成：
              value = "article.is_followed"
              @input = "article.is_followed = $event" -->
          <!-- 一个model只能使用一次在一个组件中
            如果有多个数据需要实现类似v-model效果
            可以使用属性的.sync修饰符 -->
          <follow-user 
            class="follow-btn"
            v-model="article.is_followed"
            :user-id="article.aut_id"
            
          />          
          <!-- <van-button
            v-if="article.is_followed"
            class="follow-btn"
            round
            size="small"
            :loading="followloading"
            @click="onFollow"
          >已关注</van-button>
          <van-button
            v-else
            class="follow-btn" 
            type="info" 
            color="#3296fa" 
            round 
            size="small" 
            icon="plus"
            :loading="followloading"
            @click="onFollow" 
          >关注</van-button> -->

        </van-cell>

        <!-- 文章内容 -->
        <div 
          class="article-content markdown-body" 
          v-html="article.content"
          ref="article-content">
        </div>
        <van-divider>正文结束</van-divider>
        <!-- 文章评论列表 -->
        <comment-list 
          :source="article.art_id"
          :list="commentList"
          @onload-success="totalCommentCount = $event.total_count"
          @reply-click="onReplyClick"
        ></comment-list>

        <!-- 底部区域 -->
        <div class="article-bottom">
          <van-button 
            class="comment-btn" 
            type="default" 
            round 
            size="small"
            @click="isPostShow = true"
          >写评论</van-button>
          <van-icon name="comment-o" :badge="totalCommentCount" color="#777" />
          <collect-article 
            v-model="article.is_collected"
            :article-id="article.art_id"/>
          <!-- <van-icon color="#777" name="star-o" /> -->
          <like-article
            v-model="article.attitude"
            :article-id="article.art_id">
          </like-article>
          <!-- <van-icon color="#777" name="good-job-o" /> -->
          <van-icon name="share" color="#777777"></van-icon>
        </div>

        <!-- 评论弹出层 -->
        <van-popup 
          v-model="isPostShow" 
          position="bottom">
          <comment-post
            :target="article.art_id"
            @post-success = "onPostSuccess"
          ></comment-post>
        </van-popup>
      </div>

      <!-- 加载失败：404 --> 
      <div v-else-if="errStatu === 404" class="error-wrap">
        <van-icon name="failure" />
        <p class="text">该资源不存在或已删除！</p>
      </div>

      <!-- 加载失败：其它未知错误（例如网络原因或服务端异常） -->
      <div v-else class="error-wrap">
        <van-icon name="failure" />
        <p class="text">内容加载失败！</p>
        <van-button 
          class="retry-btn"
          @click="loadArticle">
        点击重试</van-button>
      </div>
    </div>

    <!-- 评论回复 -->
    <!-- 弹出层是懒渲染的：只有在第一次展示的时候才会渲染里面的内容
      之后他的关闭和显示都是在切换内容的显示和隐藏 -->
    <van-popup 
      v-model="isReplyShow" 
      position="bottom"
      style="height: 100%;">
      <!-- v-if 条件渲染
        true: 渲染元素节点
        false：不渲染 -->
      <comment-reply
        v-if="isReplyShow"
        :comment="this.currentComment"
        @close="isReplyShow = false"
      ></comment-reply>
    </van-popup>
  </div>

</template>

<script>
import { getArticlesById } from "@/api/article"
import { ImagePreview } from "vant"
import FollowUser from "@/components/follow-user"
import CollectArticle from "@/components/collect-article"
import LikeArticle from "@/components/like-article"
import CommentList from "./components/comment-list"
import CommentPost from "./components/comment-post"
import CommentReply from "./components/comment-reply"

// ImagePreview({
//   images: [
//     'https://img01.yzcdn.cn/vant/apple-1.jpg',
//     'https://img01.yzcdn.cn/vant/apple-2.jpg',
//   ],
//   //起始位置,从0开始
//   startPosition: 1,
//   onClose () {
//     console.log('onClose');
//   }
// })

export default {
  name: 'ArticleIndex',
  data () {
    return {
      article: {}, //文章详情
      loading: true, //加载中的 loading 状态
      errStatu: 0, //失败的状态码
      followloading: false, //控制关注加载状态
      totalCommentCount: 0,
      isPostShow: false, //控制评论弹出层
      commentList: [],
      isReplyShow: false,
      currentComment: {} //当前评论的内容
    }
  },
  // 给后代组件提供数据
  provide: function () {
    return {
      articleId: this.articleId
    }
  },
  components: {
    FollowUser,
    CollectArticle,
    LikeArticle,
    CommentList,
    CommentPost,
    CommentReply
  },
  props: {
    articleId: {
      type: [Number, String, Object],
      required: true
    }
  },
  created () {
    this.loadArticle()
  },
  activated(){
    this.loadArticle()
  },
  methods: {
    async loadArticle () {
      this.loading = true
      try {
        const { data } = await getArticlesById(this.articleId)
        // if (Math.random() > 0.5) {
        //   JSON.parse('dsankdskhsghjksd')
        // }
        this.article = data.data
        // 初始化图片点击预览
        // console.log(this.$refs['article-content'])
        setTimeout(() => {
          this.previewImage()
        }, 0);
        // console.log(data);
        // 请求成功，关闭loading
      } catch (err) {
        if (err.response && err.response.status === 404) {
          this.errStatu = 404
        }
        console.log('文章加载失败',err);
      }
      // 无论成功还是失败，都需要关闭 loading
      this.loading = false
    },
    previewImage () {
      //得到所有的img节点
      const articleContent = this.$refs['article-content']
      const imgs = articleContent.querySelectorAll('img')
      const images = []
      imgs.forEach((img,index) => {
        images.push(img.src)
        img.onclick = () => {
          ImagePreview({
            images,
            //起始位置,从0开始
            startPosition: index,
          })
        }
      })

    },
    onPostSuccess (data) {
      // 关闭弹出层
      this.isPostShow = false
      // 将发布内容显示到列表顶部
      this.commentList.unshift(data.new_obj)
      this.totalCommentCount++
    },
    onReplyClick (comment) {
      // console.log(comment);
      this.currentComment = comment 
      // 显示评论回复弹出层
      this.isReplyShow = true
    }
  }
}
</script>

<style scoped lang="less">
@import "./github-markdown.css";
.article-container {
  .main-wrap {
    position: fixed;
    left: 0;
    right: 0;
    top: 92px;
    bottom: 88px;
    overflow-y: scroll;
    background-color: #fff;
  }
  
  .article-detail {
    .article-title {
      font-size: 40px;
      padding: 50px 32px;
      margin: 0;
      color: #3a3a3a;
    }

    .user-info {
      padding: 0 32px;

      .avatar {
        width: 70px;
        height: 70px;
        margin-right: 17px;
      }

      .van-cell__label {
        margin-top: 0;
      }

      .user-name {
        font-size: 24px;
        color: #3a3a3a;
      }

      .publish-date {
        font-size: 23px;
        color: #b7b7b7;
      }

      .follow-btn {
        width: 170px;
        height: 58px;
      }
    }

    .article-content {
      padding: 55px 32px;

      /deep/ p {
        text-align: justify;
      }
    }
  }

  .loading-wrap {
    padding: 200px 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #fff;
  }

  .error-wrap {
    padding: 200px 32px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: #fff;

    /deep/.van-icon {
      font-size: 122px;
      color: #b4b4b4;
    }

    .text {
      font-size: 30px;
      color: #666666;
      margin: 33px 0 46px;
    }

    .retry-btn {
      width: 280px;
      height: 70px;
      line-height: 70px;
      border: 1px solid #c3c3c3;
      font-size: 30px;
      color: #666666;
    }
  }

  .article-bottom {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    justify-content: space-around;
    align-items: center;
    box-sizing: border-box;
    height: 88px;
    border-top: 1px solid #d8d8d8;
    background-color: #fff;

    .comment-btn {
      width: 282px;
      height: 46px;
      border: 2px solid #eeeeee;
      font-size: 30px;
      line-height: 46px;
      color: #a7a7a7;
    }

    .van-icon {
      font-size: 40px;

      .van-info {
        font-size: 16px;
        background-color: #e22829;
      }
    }
  }
}
</style>